dm crypt: fix remove first_clone

Get rid of first_clone in dm-crypt

This gets rid of first_clone, which is not really needed.  Apparently, cloned
bios used to share their bvec some time way in the past - this is no longer
the case.  Contrarily, this even hurts us if we try to create a clone off
first_clone after it has completed, and crypt_endio has destroyed its bvec.

Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 1dc2c62200ee97b9b06cf406c7cbbd9f1eaa757d..339b575ce07fed28557a4ed6a5216d2830758bca 100644 (file)
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -33,7 +33,6 @@
 struct crypt_io {
        struct dm_target *target;
        struct bio *base_bio;
-       struct bio *first_clone;
        struct work_struct work;
        atomic_t pending;
        int error;
@@ -380,9 +379,8 @@ static int crypt_convert(struct crypt_config *cc,
  * This should never violate the device limitations
  * May return a smaller bio when running out of pages
  */
-static struct bio *
-crypt_alloc_buffer(struct crypt_io *io, unsigned int size,
-                   struct bio *base_bio, unsigned int *bio_vec_idx)
+static struct bio *crypt_alloc_buffer(struct crypt_io *io, unsigned int size,
+                                     unsigned int *bio_vec_idx)
 {
        struct crypt_config *cc = io->target->private;
        struct bio *clone;
@@ -390,12 +388,7 @@ crypt_alloc_buffer(struct crypt_io *io, unsigned int size,
        gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
        unsigned int i;
 
-       if (base_bio) {
-               clone = bio_alloc_bioset(GFP_NOIO, base_bio->bi_max_vecs, cc->bs);
-               __bio_clone(clone, base_bio);
-       } else
-               clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
-
+       clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
        if (!clone)
                return NULL;
 
@@ -498,9 +491,6 @@ static void dec_pending(struct crypt_io *io, int error)
        if (!atomic_dec_and_test(&io->pending))
                return;
 
-       if (io->first_clone)
-               bio_put(io->first_clone);
-
        bio_endio(io->base_bio, io->base_bio->bi_size, io->error);
 
        mempool_free(io, cc->io_pool);
@@ -618,8 +608,7 @@ static void process_write(struct crypt_io *io)
         * so repeat the whole process until all the data can be handled.
         */
        while (remaining) {
-               clone = crypt_alloc_buffer(io, base_bio->bi_size,
-                                          io->first_clone, &bvec_idx);
+               clone = crypt_alloc_buffer(io, base_bio->bi_size, &bvec_idx);
                if (unlikely(!clone)) {
                        dec_pending(io, -ENOMEM);
                        return;
@@ -635,21 +624,11 @@ static void process_write(struct crypt_io *io)
                }
 
                clone->bi_sector = cc->start + sector;
-
-               if (!io->first_clone) {
-                       /*
-                        * hold a reference to the first clone, because it
-                        * holds the bio_vec array and that can't be freed
-                        * before all other clones are released
-                        */
-                       bio_get(clone);
-                       io->first_clone = clone;
-               }
-
                remaining -= clone->bi_size;
                sector += bio_sectors(clone);
 
-               /* prevent bio_put of first_clone */
+               /* Grab another reference to the io struct
+                * before we kick off the request */
                if (remaining)
                        atomic_inc(&io->pending);
 
@@ -965,7 +944,6 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
        io = mempool_alloc(cc->io_pool, GFP_NOIO);
        io->target = ti;
        io->base_bio = bio;
-       io->first_clone = NULL;
        io->error = io->post_process = 0;
        atomic_set(&io->pending, 0);
        kcryptd_queue_io(io);